Electric switch



Oct. 12 1926.

1,603,078 J. D. HlLLlARD ELECTRIC SWITCH Filed April 28, 1926 HLs Attorney.

Patented Oct. 12, 1926.

UNITED STATES PATENT OFFICE.

JOHN D. HILLIARD, OF SCHENEC'I'ADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC SWITCH.

Application filezFA'pril 28, 1926. Serial No. 105,286.

My invention relates to high potential electric switches, and particularly those of the explosion chamber fluid break type. An object of my invention is to provide a switch of this type having improved means for relieving the explosion chamber thereof of excessive pressure, thereby increasing the capacity of the switch.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

Referring to the drawing of which the single figure shows in section a switch embodying my invention, 1 is the lower end of an insulator bushing which projects down into the insulating liquid in the switch tank, and by which a fixed contact of the complete switch is supported. For a more complete showing of such a switch, reference is had to the Huber Patent 1,546,173, July 1 1, 1925. The clamping plate 2, secured on the end of the stud 3 against the bushing 1 has mounted thereon the adapter 4, which may be held in various positions of angular adjustment thereon by the clamping ring 5.. In the embodiment shown, the lower portion 6 of the adapter forms the upper plate or wall of the explosion chamber casting 7 the bottom of which has an opening in which is secured the bushing 8, having the restricted throat 9. The explosion chamber 7 is shown surrounded by the cylinder 10 of insulation and having the insulation lining 11.

Threaded into the plate portion 6 is the shield 12, whose purpose will be pointed out later, and threaded in the shield 12 is the retainer 13 for the fixed contact 14. This latter is of cylindrical or tubular form and comprises a number of segments arranged within the cage 15 and pressed inwardly therefrom by springs 16. The contact retainer 1.3 is closed-at the top by the cap 18 to which the cage 15 is afiixed, and to which good electrical connection is made with the segments by the flexible conductors 19. The lower end of the bushing 1 and the parts carried thereby being immersed in the insulating liquid, it is necessary to provide the retainer 13 with a small vent opening 20 in the cap thereof whereby air or gas may escape to permit the holder to completely fill with the liquid. The holder 13 has a downward extension 22 forming an arcing ring to which the arc is quickly transferred from the fixed contact when the movable contact rod 23 is withdrawn. The upper portion of extension 22 also serves to limit downward movement of the fixed contact and passages 24 are provided therein for the escape of liquid and gas, which may be discharged between the segments of the fixed contact into the chamber 26 formed by the shield 12. 'At the bottom of the shield is an opening in which is mounted the insulation bushing 27 through which passes the contact rod 23. The shield 12 divides the casing 7 into two connecting explosion chambers the smaller one 26 of which is in direct communication with the fixed contact. In order that-the gas and liquid may be quickly dis-""ar ed from the chamber 26, I provide anumber of discharge openings leading therefrom and arranged close to the fixed cont-act. By way of example, I have shown a plurality of openings 28 around the fixed contact in the top of the casing. They may, however, be otherwise located as for example, in the retainer 13. A small bleed hole 29 is shown in the top of the explosion chamber outside of the shield whereby any air or gas in the chamber may escape to permit the chamber to fill completely with liquid.

In'operation upon withdrawal of the contact rod from the fixed contact in the cir cuit opening movement of the switch, a large part of the gas initially produced by the resulting are as the contact rod descends, can escape from the explosion chamber with comparative freedom through the chamber 26 and "he discharge openings 28, thereby relieving the exlplosion chamber casing of excessive pressure during the movement of the rod 23 through the throat 9. It is of course intended to have a suflicient flow of insulating liquid through the throat 9 to finally extinguish the are, but it is undesirable to force; more than this' amount from the explosion chamber. By arranging the fixed contact and the gas discharge openings at the top of the explosion chamber much of the gas can escape therefrom without first expelling the mass-of liquid lying below and before this mass has had time to esca e through the throat 9. The size of t e throat 9 can thereby be materially reduced over what would be necessary were all of the gas discharged therethrough. Only the relatively small amount of liquid contained within the shield 12 is ejected prior to or with the gas through the discharge openings 28 after which there may be a comparatively :tree flowof gas'from the explosion chamber. This means that a lower pressure prevails in the explosion chamber than is the case where the mass of liquid must first be put into motion and expelled'before there can be an escape of gas resulting in certain cases in a needlessly high pressure in the explosion chamber. By reducing the size of the throat 9 the liquid in the casing 7 is conserved during the downward movement therethrough of the rod 23 for use in extinguishing the are after the rod is withdrawn.

hat I claim as new and desire to secure by Letters Patent of the United States is 1. A fiuid break switch comprising means forming two connecting explosion chambers one of which is relatively small, a fixed contact associated with the small chamber, a movable contact arranged to be withdrawn from the fixed contact successively through the two chambers, said small chamber having means adjacent the fixed contact for the quick discharge of gas therefrom.

2. A fluid break switch comprisingv a casing forming two connecting explosion chambers of different sizes, a fixed contact arranged at a wall of the smaller of said chambers, a movable contact arranged to be withdrawn from the fixed contact successively through the smaller and the larger of said chambers, said smaller chamber having openings in said wall and adjacent said fixed contact for the quick discharge of gas therefrom.

3. A fluid break switch comprising 00- operating fixed and movable contacts immersed 1n an insulating liquid, a casing forming an explosion chamber enclosing the fixed contact and having an opening therein through which the movable contact is Withdrawn when moved to open circuit position,

said casing comprising means forming a smaller chamber therein for the fixed contact and having gas discharge passages leading therefrom.

4. A fluid break switch comprising co operating fixed and movable contacts immersed in an insulating liquid, an explosion chamber casing having an opening in the lower wall thereof through which the movable contact is withdrawn when moved to open circuit position, said casing having gas discharge passages adjacent the fixed contact and having means forming a gas discharge chamber connecting the fixed contact with the gas discharge passages.

5. A fluid break switch comprising cooperating fixed and movable contacts immersed in an insulating liquid, an explosion chamber casing having an opening in the lower wall thereof through which the movable contact is withdrawn when moved to open circuit position, said fixed contact being arranged at the upper portion of the explosion chamber casing and being surrounded by gas discharge openings, and a shield surrounding the lower portion of the fixed contact through which gas is freely conducted to the gas discharge openings.

6. A fluid break switch comprising cooperating fixed and movable contacts immersed in an insulating liquid, an explosion chamber casing having a restricted opening in the lower wall thereof through which the movable contact is withdrawn when moved to open circuit position, said casing having the fixed contact mounted in its upper wall and having gas discharge passages around the fixed contact and a depending shield in the casing having an opening for the movable contact and forming a chamber with the upper wall of the casing connecting the fixed contact and the gas discharge passages.

In witness whereof, I have hereunto set no my hand this 27th day of April, 1926.

JOHN D. HILLIARD. 

